There can be few more unpleasant tasks a sheep owner has to deal with than a case of blowfly strike. Or to use a more scientific term cutaneous myiasis. Or much more simply a case of maggot infestation. Over the years we’ve had the occasional case, usually in very hot humid weather, often quite late in the year. And usually just a single sheep that’s had a slightly mucky rear which has attracted the flies to the smell. The flies lay eggs onto the soiled fleece, the eggs soon hatch into first-stage maggots, which quickly mature, go through 3 larval forms as they rapidly grow and secrete flesh-damaging enzymes. Surprisingly quickly the poor animal can begin to be eaten alive. The initial attack is usually by green bottle flies, Lucilia sericata, and once skin becomes damaged by maggot activity, other flies are attracted to the scene.

Many commercial farmers will routinely treat the whole of their flock with a pour-on insecticidal liquid, these days often containing a synthetic pyrethroid-type chemical. In days gone by, most sheep were dipped with even more toxic chemicals, like organophosphates with even worse safety profiles for livestock, invertebrates and indeed the farmer using it. Permethrins are safer but are still quite broad-spectrum agents that can harm many invertebrates, so on risk-benefit grounds, rather as with the routine use of any anthelmintics (wormers), or indeed vaccines, we stopped using them several years ago for our small, low-density flock. The downside to this is we have to be alert to the telltale early signs of problems – restlessness on the part of the sheep, turning round suddenly and nibbling at a part of the body, and a slight discolouration of the fleece. This year, despite not having really muggy, or hot weather, and even though none of the sheep have any soiling, we’ve recently had one of the worst cases ever. It seems we’re not alone, and this must in part be due to fleeces being saturated for weeks on end. It required two separate sessions of manually clipping back the wool from obviously affected areas, scraping away the small maggots with the dagging shears, and then applying the cypermethrin around the area. In the case of “Hoopoe”, this meant grabbing her at the furthest point of our land, beyond the stream, on a steep slope amongst trees, and bracing myself against a trunk for stability, whilst Fiona did the manual clip-out and treatment. The maggots are killed quite quickly and fall to the ground, but it’s only after doing this that the full extent of the damage becomes apparent. There are no action photos of this – it would be too gruesome for most, and anyway, all efforts and hands are involved in completing the task. (There are plenty of gory images on the link above).

 

By the second day, and after a second treatment application, she was sufficiently improved to be persuaded to leave her shaded, hunkered down “refuge” (except of course, there are no real refuges from the flies), cross the stream, and slowly follow Fiona through the lower meadow towards where we’d moved the rest of the flock for individual checks, clip offs, and preventative applications – in the end half a dozen or so were showing very early signs of a problem.

As we reached the lower hay meadow, which had good aftermath regrowth from our mid-June early hay cut, she suddenly sped up, and after walking about 20 yards past lush grass, stopped for her very first bite at the first clump of ribwort plantain, Plantago lanceolata, she came across. This was the best confirmation of the merits of a real ‘cae ysbyty’, (a traditional Welsh farm ‘hospital field’) that we’ve ever witnessed. An animal self-selecting a plant with known anti-inflammatory pharmacological activity, which I’ve written about before.

When we amalgamated the flock again and moved them all back into this same field, there was more evidence about how the sheep self-select particular plants, in a way they can’t manage in most species poor Welsh upland pasture.

One of the reasons we delay putting them back into this lower meadow for so long is to allow the early form of Devil’s-bit scabious, DBS, (which I’m gradually propagating from seed, and re-introducing as small root-trained plants), to set seed before the sheep come in and snaffle the seed heads.

I’d known for some time that the common name of the plant, Succisa pratensis, is thought to have arisen because of the odd appearance and sudden blunt ending to the black roots. (Succisa = ‘cut down’ underneath, pratensis = ‘meadow’) Almost as though they have been bitten off. Every reference to the plant mentions this, although I couldn’t find a single image to illustrate it. So I thought that I should dig up one of my root-trained plants which had been planted onto our bank of peril this spring, to confirm this. And this is what I found, after washing off most of the soil. Firstly, the roots seem very well-developed and largely white, but secondly, I’d struggle to identify any sections that look as though they’ve been bitten off. Looked at in detail, they are a little unusual in form, at least in places, but hardly enough to make one describe it as it has been historically, as bitten off.

What about the scabious part of the name? Again, it’s often mentioned that for centuries it was used to treat skin inflammation and human scabies – caused by the parasitic mite, Sarcoptes scabiei. And was even used to treat skin sores caused by the bubonic plague. Some sites suggest it has anthelmintic properties, and is a useful immunostimulant. Nicholas Culpeper (1616-54) thought highly of its medicinal properties and wrote “The root was longer until the devil bit it away, envying its usefulness to mankind”.

Eventually, on a site curated by the Royal College of Physicians, Garden of Medicinal Plants, I found this corroborating quote, by Dr Henry Oakley for my apparent debunking of the bitten root etymology: “Folklore attribute it as a cure-all which was so successful that the Devil bit off the bottom of the roots when he saw it growing down into Hades. However, the roots show no sign of such damage to support the myth.” 

It’s surprising how easily myths can come to be perpetuated online, isn’t it? Although it does leave me wondering just why it came to get this common, and scientific (Latin) name. Might its morphology have changed over decades, or might there be variants in other parts of the world, or different conditions, where the root system does looked as though it’s been chomped? Who knows.

 

It takes a bit of digging sometimes to get closer to the truth, perhaps…

Whatever, it seems that the plant’s known medicinal attributes certainly merit it having a place in our cae ysbyty, aside from its tremendous aesthetic and invertebrate interest.

HOWEVER. I think something else which is very curious about this plant may indeed still irk the devil in more contemporary times.

While separate sexes are thought of as the norm in much of the animal world, they are the exception in flowering plants.

It turns out that DBS is one of a very small population of angiosperm species (all flowering plants) which is gynodioecious (a new word for me). These odd angiosperms (I decided against using the adjective queer) produce both typical hermaphrodite flowers (as most flowers are, with both male pollen-producing anthers and female stigmas leading to ovaries and ovules for seed production)  AND also produce, on the same plant – not separate ones – flowers that simply have entirely female structures, the male parts of these flowers having been aborted.

Taxonomists have discovered that such plants, of which there are maybe only 2% of the total number of flowering plants, are widely distributed throughout the genera of flowering plants and tend to be in the terminal branches of plant evolutionary development. There are only about 6% of plants that are dioecious, with separate male and female flowers produced on different plants.

Many plant genera will just have a few species with these gynodioecious characteristics. This led evolutionary biologists to speculate that the mutations responsible for these peculiar traits have emerged on multiple separate occasions. But it’s thought that the ‘gynodioecy–dioecy pathway’ is one of the most important evolutionary routes from hermaphroditism to separate sexes in life on earth.

Even more curious, is how this process is thought to occur. Most of the scientific papers I dipped into were pretty incomprehensible to me, and the simplest, no doubt dumbed down, explanation that I read I’m including in part below (albeit slightly re-written by me for clarity). This explains just what a battle is going on at a cellular level:

“Gynodioecy develops as a result of a genetic mutation that stops a plant from producing pollen, but still allows normal female reproductive features to exist.

In all plants, the cell’s nuclear genes are inherited from both parents, but all the cytoplasmic genes come from the mother. This allows male sex cells (gametes) to be smaller and more motile while female gametes are larger. It makes sense for most plants to be hermaphrodites since they can’t move around and so are unable to find mates as easily as animals can.

Cytoplasmic male sterility genes exist, usually found in the mitochondrial genome, and become established when female fertility is just slightly more than the hermaphroditic fertility. Research has shown that in typical hermaphroditic plants, there are constant battles against organelle genes trying to kill their male parts. Male sterility genes can cause plants to grow anthers that are stunted or withered and as a result, do not produce pollen. In most plants, however, there are also nuclear fertility-restoring genes that counteract the work of the male sterility genes, maintaining the hermaphroditic state of the plant.

However, in just a few species of plants, the male sterility genes win the battle over the nuclear fertility restoring genes, and gynodioecy occurs.”

So it seems that in DBS, the plant’s male sterility genes have indeed won the battle, at least partially, and gynodioecy with female flowers, with shrivelled anthers, has become possible.

Who would have thought all this complex biochemistry and genetics underpinned such a beautiful range of native flowers with such wide insect appeal and replete with pharmacologically active chemicals of benefit to many animals.

But maybe, just maybe, in today’s world where I struggle to comprehend the extent to which gender issues in Homo sapiens seem to be an ever-present, inescapable subject of debate, the devil might have the last laugh. And decide to do a better job this time, and really get to grips with the DBS roots. 

Or then again, why wouldn’t he/she/it just leave things as they are.

And smirk.

Interestingly, other meadow plants including some plantains, and also Geranium sylvaticum, which I first saw growing in meadows in Northumberland are also gynodioecious. Before finally leaving the vexed subject of DBS, and at risk of being considered to be a little DBS obsessed of late, I can relate another special moment when I was fixated on a single small DBS flower at the margin of our lower wet meadow this week.

I’d walked past it as one of a group of DBS plants I’d planted out a year ago along the ditch margin, to be certain that they wouldn’t get scythed off when the hay was cut.

My eye was caught by a distinctive white crab spider, Misumena vatia, sitting atop this flower, with its front legs spread wide, waiting to grab a passing insect rash enough to land on the flower. As I moved past, my shadow crossed it, and it quickly scuttled beneath the flower head to a degree of safety.

I walked on, and turning back after a few yards, spotted it moving back onto the flower head. I was a little surprised it had ventured back into full view so quickly, and more carefully moved closer to take a few clearer photos. As I had the viewfinder to my eye, and with the lowering sun behind me, I was amazed to see it change its posture, stick its pointed abdominal tip into the air in an almost Ian Fleming-like SPECTRE posture, and quite suddenly and rapidly emit an orgasmic multi-strand burst of silk fibres, which diverged and glinted in the sunlight.

The light breeze moved these around a bit, and the spider then changed its position, and fairly quickly began to tweak the silk fibres with its front set of legs, which were now held to its front. It repeated this pattern of quite regular rotation on the flower head, silk squirts and reeling in, over many minutes. In a few photos, you can even make out a small bundle of silk, gathered beneath its head. What on earth was going on? I’d never seen anything like it and began to wonder if the spider was using the fibres a bit like a fishing line – casting them out, and hauling them in, hoping to have caught a small insect.

Was it indeed a crab spider, or some other species, although it looked just like crab spiders I’ve occasionally seen before. But they’ve always sat completely still on the flower, using stealth to catch their prey.

In the end, some recent research at Bristol University which I tracked down explained it all, beautifully. It was after all a crab spider, but it wasn’t trying to catch food – indeed it had ignored two potential meals whilst I was crouched still, photographing it.

Rather it seems it had decided it was time to move on.

Or more specifically, that it was time to take to the air, in what I now know is referred to as ballooning. Do watch the EXCELLENT video included by the researchers at Bristol in this published paper about their study. (Electric Fields Elicit Ballooning in Spiders, by Erica Morley and Daniel Robert). It’s a very readable piece, with some nice footage and graphics, which I can’t embed directly in this post.

They’ve worked out that small but significant changing electrostatic forces in the air can be detected by tiny hairs on spiders’ legs, and when the winds are light (as they were on this afternoon), and there is sufficient electrostatic charge in the air, they’ll adopt the characteristic tip toe posture above. They then emit the multi-strand silk which is kept apart and drawn from the spider’s spinnerette organs so fast precisely because of these electrostatic charges. Then, with good fortune, the spider will be dragged off the flower, becoming airborne, and potentially travelling thousands of metres into the air, and depending on the wind direction, could be relocated hundreds of miles away. Sadly my failing camera battery and painful knee meant I hadn’t stayed long enough to see if this actually happened.

The following morning I returned to check both the sheep, and the flower, and to see whether the spider was still there. It wasn’t. Checking the prevailing wind direction and speeds at the time I’d witnessed this behaviour showed that if it had been dragged upwards, there’s an outside chance it might have made it to France. Or more likely South East Wales, Bristol or even London.

But who knows, maybe it landed just on the other side of the valley. Or had been eaten by a hungry predator. However, managing to witness and photograph the actual moment of multi-stream explosive shot-silk ranks as one of my very special sightings in all our time here. Piecing together what was actually going on, and discovering a spider’s ability to detect these charges was even more amazing.

And it also made me speculate on how other insect behaviour might be influenced by such electrostatic charges. In what’s been a really poor summer for our honey bees’ ability to forage for nectar and pollen, we’re approaching a time of the year, when the robbing of honey from colonies becomes likely. One colony was already showing signs of failing after many of the workers and their productive queen swarmed into the empty German butter churn box box earlier in the year. I even wondered if this hive, fixed up a larch tree, had itself been taken over by another small swarm a few weeks ago. Whatever had happened, wasps had already clearly been gaining access in small numbers for the last 10 days, without obvious signs of active defence. Yesterday morning, despite the drizzle, it was suddenly violently robbed out by a large invasion of bees from a colony somewhere, possibly off our land.

Meanwhile an hour after I’d seen the crab spider, I was hunting for more clear examples of female DBS flowers (they don’t seem as common as the hermaphrodite ones) in the upper hay meadow, and trying to get some nice photos of a common carder bumblebee, Bombus pascuorum, visiting them.

When out of the blue I got charged and buzzed by an angry honey bee. This was the first time this had happened to me in months, and I was well away and out of sight of any of the hives. Might this just have been a result of increased tension with the closest hive, because of wasp attacks? And a hyped-up guard bee exploring well beyond the hive entrance for potential threats? Or might the level of electrostatic charge in the air which the spider had obviously detected been responsible for an increased state of agitation?

Who knows, but I retreated in haste from this unprovoked attack and pondered how insensitive we are to such subtleties of the environment around us, compared with these “lower” forms of life that have to survive and thrive outside in these tricky and fickle local conditions. 

A final DBS-related episode was a new species of hoverfly found here which was regularly working the row of DBS flowers where I’d seen the spider the afternoon before. Behaving and looking just like a B. pascuorum, this is an appropriately named Furry Peat hoverfly, Sericomyia (Arctophila) superbiens.  It’s largely restricted in distribution to the West and North of the UK and has a larval form that probably – no one is certain – lives in peaty puddles in damp, acid parts of the country. It’s typically on the wing late in the year and prefers visiting DBS flowers as one of its favourite food sources.

In between all this excitement (well it makes a change from moaning about the weather), we managed, just, to take another section of hay from our upper meadow in another very brief half-weather window – yet again 48 hour hay only possible as a result of multiple turnings and help once more on the final day from Andy (thanks again Andy!) in pushing it all into big piles, before Fiona and I rushed to bring it in, mid-afternoon, as the sunshine-all-day forecast had morphed into heavy clouds, and showers threatened once more.

One spin-off of the haymaking was me getting up early on the final, glorious and supposedly hot sunny day, to a fabulous scene of mist in the valleys and sunlight shafting through the trees along the green lane.

We also had what may turn out to be our last garden visitors of the year, in what has been our busiest ever season for the NGS, and yet another first with a couple from the village booking in with their parents, just 3 days after tying the knot. And a group of 4 intrepid folks travelling all the way from Wiltshire to visit. It was lovely to spend time with them all, and they were all very fortunate to escape any significant rain whilst here. Even if they missed the real breaks in the cloud,

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Finally, as my musical epilogue, I’d been thinking of including another piece for this post, but given the spider sighting, I thought I’d include the probably very familiar Louis Armstrong piece “We Have All the Time in the World”. 

I’d suggested watching the film, “No Time to Die”  to Fiona last weekend, (for just the second time) as a bit of total escapism from the largely damp, gloomy Gelli scene, so we dug out the DVD and put it on. You always notice different things on a second viewing apart from the extraordinary synchronicity of the plot line and title…

(Now there’s a curious, devilish resemblance, eh?)

This played out as the Covid-19 pandemic was just about to emerge into the world, and the symbol of the SPECTRE organisation was fresh in my mind when the crab spider tiptoed in front of me just days later.

It’s also interesting that the song was written by John Barry, (the minimalist lyrics by Hal David) who married, in 1965, a much younger 19-year-old Jane Birkin (who died just a month ago). The song first appeared in the 1969 James Bond film “On Her Majesty’s Secret Service”, before getting its reprise as the closing song for Daniel Craig’s last appearance as Bond. If the song was influenced by his marriage to Jane, it was poorly judged – the marriage was dissolved in 1968 – possibly around the time the song was being penned? Armstrong’s iconic voice transforms the song, even though he was apparently so unwell when it was recorded that someone else, possibly Herb Alpert, was asked to play the trumpet solo.